The present invention is directed to spin-on filter assemblies. More particularly, the present invention is directed to high pressure, spin-on filter assemblies which are optionally rebuildable.
Spin-on filter assemblies are used for a number of purposes such as, but not limited to, filtering hydraulic fluid, filtering lubrication oil for machinery and internal combustion engines and for filtering transmission oil.
Primarily applications for such filters are high-pressure hydraulic systems which use spin-on filters. These filters have housings which are usually made of steel and are high volume items sold for both the original equipment and replacement market. Lately, there has been considerable interest in providing filter assemblies in which the filter housing is reusable. There are of course environmental concerns which arise when a used filter having hydraulic oil, or any other filtered liquid therein, is disposed of in its entirety because not only does the filter housing end up in a land fill, but also the filter media and liquid within the housing. In some situations, this is still acceptable, but in other situations it is not. Accordingly, there is a need for filter assemblies which are in effect rebuildable by removing the filter element which contains the filter media therefrom so that the only item which must be disposed of is the filter media itself. When the housing is opened, hydraulic fluid therein can be drained therefrom, refined and reused or disposed of in an acceptable manner, instead of being disposed of while contained within a filter housing.
Generally, it is preferable to have as few parts for a particular item as necessary. According to current practice, one spin-on filter assembly is manufactured for situations in which the entire assembly is disposed of and another spin-on assembly configuration manufactured for rebuildable spin-on filter assemblies. This results in an overall increase in cost.
In view of the aforementioned considerations, the present invention is directed to a filter assembly comprising an annular can having a first closed end and a second open end. The second open end has a coupling arrangement adjacent thereto for receiving a first base member which is not removable therefrom when coupled thereto, so as to provide filter assembly which is disposed of in its entirety with a used filter media inside, and a second base member which is removable from the can to provide a rebuildable filter assembly in which only the used filter media therein is disposed of.
More specifically, the present invention is directed to a filter assembly comprising a can having first and second ends, the first end being closed and the second end being open, wherein the can is adapted to receive a filter element. The can has an interior wall surface and coupling portion adjacent the second end of the can, wherein the coupling portion has a radially disposed, annular groove therein and an helically threaded section inboard of the groove disposed about a first axis. A base having openings therethrough adapted to provide inlet and outlet openings for fluid being circulated through the housing and through the filter element within the housing. The base has an externally threaded portion disposed about a second axis for receipt in the internal helically threaded section of the internal wall surface of the can with the first and second axes being coexistant. The base also has a radially projecting rib for receipt in the annular groove in the wall of the can to lock the base within the can, whereby the filter element is retained in the can between the first and second ends thereof. In accordance with a first arrangement, the base is permanently fixed with respect to the can and in accordance with a second arrangement the base is removable from the can so that the element can be replaced.
In order to facilitate interchangeability bases, the groove in the can, is V-shaped with one of the bases having a rib which compliments the V-shaped groove, allowing the first base to be unscrewed, and the other of the bases having a rib, which compliments only one surface of the V-shaped groove, so as to prevent the other base from unscrewing from the can.